Grissom endured many physical and psychological tests, and was chosen as one of the seven Mercury astronauts. Six others received the same notification: Lieutenant Malcolm Scott Carpenter, U.S. Navy; Captain LeRoy Gordon Cooper, Jr., U.S. Air Force; Lieutenant Colonel John Herschel; Glenn, Jr., U.S. Marine Corps; Lieutenant Commander Walter Marty Schirra, Jr., U.S. Navy; Lieutenant Commander Alan Bartlett Shepard, Jr., U.S. Navy; and Captain Donald Kent Slayton, U.S. Air Force

This photo shows Grissom dressed for his flight on July 21, 1961, he was the second pilot for Mercury-Redstone 4, commonly known as Liberty Bell 7. The flight lasted 15 minutes and 37 seconds. It reached an altitude of more than 118.26 miles and traveled about 300 miles. Photo NASA original 61-MR4-62 (8) taken on July 19, 1961 in Hanger S at Cape Canaveral, Florida. Grissom is shown with Walter Shirra. Photo is signed by Grissom on the date of the Liberty Bell 7 launch.

After splashdown, emergency explosive bolts unexpectedly fired and blew the hatch off, causing water to flood into the spacecraft. Grissom was nearly drowned. The spacecraft filled with water and was lost. Grissom was accused of opening the hatch by the press. Grissom repeated his account. “I was just laying there minding my own business when, POW, the hatch went. And I looked up and saw nothing but blue sky and water starting to come in over the sill.” (Turner Home Entertainment, Moon Shot (Atlanta: Turner Broadcasting System, Inc., 1994).

“We tried for weeks afterwards to find out what had happened and how it had happened. I even crawled into capsules and tried to duplicate all of my movements, to see if I could make the whole thing happen again. It was impossible. The plunger that detonates the bolts is so far out of the way that I would have had to reach for it on purpose to hit it, and this I did not do. Even when I thrashed about with my elbows, I could not bump against it accidentally.” (Carpenter et al., p. 227.)

The hatch is opened by hitting the plunger with the side of your fist, which would leave a large bruise,but Grissom had no such bruising. Because of this controversy, Mercury astronaut Wally Schirra, at the end of his flight stayed inside his spacecraft until it was aboard the ship, and then blowing the hatch, and bruising his hand.

Gus said “It was especially hard for me, as a professional pilot. In all of my years of flying – including combat in Korea – this was the first time that my aircraft and I had not come back together. In my entire career as a pilot, Liberty Bell was the first thing I had ever lost.”( Ibid, p. 227.)

Quote from Gus: “If we die, we want people to accept it. We’re in a risky business, and we hope that if anything happens to us it will not delay the program. The conquest of space is worth the risk of life.” (John Barbour et al., Footprints on the Moon (The Associated Press, 1969), p. 125.)